U.S. patent number 8,126,475 [Application Number 11/539,873] was granted by the patent office on 2012-02-28 for apparatus and method for uplink scheduling on shared channels.
This patent grant is currently assigned to Motorola Mobility, Inc.. Invention is credited to Ravi Kuchibhotla, Padmaja Putcha.
United States Patent |
8,126,475 |
Kuchibhotla , et
al. |
February 28, 2012 |
Apparatus and method for uplink scheduling on shared channels
Abstract
A network controller or base station (502), allocates resources
and indicates a minimum priority level below which, mobile stations
may not transmit data via messaging (503). Messaging (503) may be a
scheduling message in some embodiments. The network controller or
base station (502) also communicates a data timer setting for
timing sub-minimum priority data via messaging (505). Messaging
(505) may be a control message in some embodiments. The mobile
station (501) responds by setting a data timer (507) and holding
data with a priority below the specified minimum. Before the timer
times out, the mobile station (501) may transmit data on granted
resources via (509) provided its priority level is above the
specified minimum. After timer expiration, the mobile station (501)
may transmit its low priority data, or combinations of high and low
priority data (511).
Inventors: |
Kuchibhotla; Ravi (Gurnee,
IL), Putcha; Padmaja (Gurnee, IL) |
Assignee: |
Motorola Mobility, Inc.
(Libertyville, IL)
|
Family
ID: |
38834498 |
Appl.
No.: |
11/539,873 |
Filed: |
October 9, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080085719 A1 |
Apr 10, 2008 |
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Current U.S.
Class: |
455/452.2;
455/453; 455/450; 455/452.1; 370/395.42; 455/451 |
Current CPC
Class: |
H04L
47/805 (20130101); H04W 28/0252 (20130101); H04L
47/826 (20130101); H04W 28/0278 (20130101); H04L
47/788 (20130101); H04L 47/6285 (20130101); H04L
47/824 (20130101); H04L 47/6215 (20130101); H04L
47/14 (20130101); H04L 47/15 (20130101); H04L
47/50 (20130101); H04L 47/70 (20130101); H04W
72/1221 (20130101); H04W 72/1242 (20130101); H04W
28/14 (20130101) |
Current International
Class: |
H04W
72/00 (20090101) |
Field of
Search: |
;455/450,451,452.2,453
;370/395.2,395.21,395.3,395.31,395.32,395.4,395.41,395.42,395.43 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1315342 |
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May 2003 |
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EP |
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1545040 |
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Jun 2005 |
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EP |
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1643690 |
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Apr 2006 |
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EP |
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1681887 |
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Jul 2006 |
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EP |
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2005/125252 |
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Dec 2005 |
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WO |
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2006/071155 |
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Jul 2006 |
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WO |
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WO 2006/089568 |
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Aug 2006 |
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WO |
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Other References
International Search Report and Written Opinion; International
Application No. PCT/US2007/078398; dated Jan. 15, 2008. cited by
other .
3rd Generation Partnership Project; Technical Specification Group
Radio Access Network; FDD Enhanced Uplink; Overall description;
Stage 2 (Release 6); 3GPP TS 25.309; V6.6.0; Mar. 2006. cited by
other.
|
Primary Examiner: Perez-Gutierrez; Rafael
Assistant Examiner: Di Prisco; German Viana
Claims
What is claimed is:
1. A method of operating a network infrastructure entity, the
method comprising: mapping a set of data priorities to a set of
radio bearers, each of said radio bearers of said set of radio
bearers corresponding to a data priority of said set of data
priorities; setting a minimum data priority below which low
priority data having a priority below said minimum data priority
should not be transmitted over any of said radio bearers, wherein
said data is associated with a service; sending said minimum data
priority to a mobile station along with a resource allocation,
wherein prioritized data having a priority equal to or above said
minimum data priority is allowed to be transmitted by said mobile
station using said resource allocation; setting, by said network
infrastructure entity, a time limit for which said mobile station
may buffer said low priority data, wherein said mobile station may
transmit said low priority data using said resource allocation
after said time limit expires; and sending said time limit from
said network infrastructure entity to said mobile station.
2. The method of claim 1, wherein sending said time limit to said
mobile station further comprises: sending said time limit to said
mobile station in a control message.
3. The method of claim 1, wherein sending said minimum data
priority to a mobile station along with a resource allocation
further comprises sending a scheduling message.
4. The method of claim 1, wherein said time limit set by said
network infrastructure entity is dynamically determined based upon
network conditions.
5. A method in a mobile station, the method comprising: buffering a
first set of data having a first priority and a second set of data
having a second priority lower than said first priority; receiving
a resource allocation for transmitting said first set of data and
said second set of data; receiving a priority minimum below which
data should not be transmitted; receiving, from a base station, a
time setting for which data having a priority below said priority
minimum should not be transmitted and setting a timer according to
said time setting; determining whether said second set of data has
a priority above or below said priority minimum; receiving a data
percentage indicating an allowable data percentage of buffered said
priority minimum data, that is allowed to be transmitted;
transmitting said second set of data using said resource allocation
if said second priority is equal to or above said priority minimum;
and holding said second set of data if said second priority is
below said priority minimum, transmitting said allowable data
percentage of said second set of data after said timer expires, and
continuing to buffer data having a priority below said priority
minimum.
6. The method of claim 5, wherein receiving a priority minimum
below which data should not be transmitted, further comprises
receiving a scheduling message having said priority minimum.
7. The method of claim 5, wherein receiving a time setting for
which data having a priority below said priority minimum should not
be transmitted, further comprises receiving a control message
having said time setting.
8. A mobile station comprising: at least one transceiver; at least
one processor coupled to said transceiver; said transceiver and
said processor configured to: buffer a first set of data having a
first priority and a second set of data having a second priority
lower than said first priority; receive a resource allocation for
transmitting said first set of data and said second set of data;
receive a priority minimum below which data should not be
transmitted; receive, from a base station, a time setting for which
data having a priority below said priority minimum should not be
transmitted and set a timer according to said time setting;
determine whether said second set of data has a priority above or
below said priority minimum; receive a data percentage indicating
an allowable percentage of data stored by said buffer, said data
having a priority lower than said priority minimum, that is allowed
for transmission; transmit said second set of data using said
resource allocation if said second priority is equal to or above
said priority minimum; and hold said second set of data if said
second priority is below said priority minimum, transmit said
allowable data percentage of said second set of data after said
timer expires, and continue to buffer data having a priority below
said priority minimum.
9. The mobile station of claim 8, wherein said transceiver and said
processor are further configured to receive said priority minimum
below which data should not be transmitted, by receiving a
scheduling message having said priority minimum.
10. The mobile station of claim 8, wherein said transceiver and
said processor are further configured to receive said time setting
for which data having a priority below said priority minimum should
not be transmitted, by receiving a control message having said time
setting.
11. A base station comprising: a transceiver; a processor coupled
to said transceiver, said transceiver and said processor configured
to: map a set of data priorities to a set of radio bearers, each of
said radio bearers of said set of radio bearers corresponding to a
data priority of said set of data priorities, said set of radio
bearers further corresponding to said resource allocation; set a
minimum data priority below which low priority data having a
priority below said minimum data priority should not be transmitted
over any of said radio bearers, wherein said data is associated
with a service; send said minimum data priority to a mobile station
along with a resource allocation, wherein prioritized data having a
priority equal to or above said minimum data priority is allowed to
be transmitted by said mobile station using said resource
allocation; setting a time limit for which said mobile station may
buffer said low priority data, wherein said mobile station may
transmit said low priority data using said resource allocation
after said time limit expires; and sending said time limit to said
mobile station.
12. The base station of claim 11, wherein said transceiver and said
processor are further configured to: send said time limit to said
mobile station in a control message.
13. The base station of claim 12, wherein said transceiver and said
processor are further configured to send a data percentage
indicating a percentage of data stored by said buffer, said data
having a priority lower than said priority minimum, for
transmission after said timer expires.
14. The base station of claim 12, wherein said data is a plurality
of protocol data units.
15. The base station of claim 11, wherein said transceiver and said
processor are further configured to send said minimum data priority
to said mobile station along with a resource allocation by sending
a scheduling message.
Description
FIELD OF THE DISCLOSURE
The present disclosure relates generally to quality of service on a
communications channel and more particularly to methods and
apparatuses for scheduling uplink data transmissions to maintain
quality of service requirements.
BACKGROUND
Wireless communications systems, for example packet data
communications systems, may utilize shared channels wherein the
network allocates resources to a mobile station for uplink
transmissions based on the number of mobiles requesting resources,
the channel conditions of the mobile station, and the services for
which the mobile station is requesting resources.
The mobile station will transmit information to the network
regarding a buffer status of each radio bearer or for a group of
radio bearers. Typically each service utilized by the mobile
station is mapped to one radio bearer. Each service and thus, each
radio bearer, is associated with a priority. In order to minimize
the amount of signaling overhead, it is preferred to have a mobile
station indicate the amount of data in its buffer across all radio
bearers and indicate for example, the highest priority radio bearer
that has data waiting to be sent. This allows the network to assign
resources with some degree of fairness.
However, since the network does not have the absolute latest
information regarding each and every radio bearer it typically will
assign resources to a mobile station that may be used to transmit
data from a number of radio bearers. One issue with such a
mechanism is that the network is not in control of the exact usage
of resources by the mobile station.
For example, the mobile station may have data in the buffer for
radio bearer (RB) #1, 2, 3 and 4, wherein the sequence number also
indicates a priority of the data. For example, RB #4 may indicate
the lowest priority data while RB#1 may indicate the highest
priority data.
However, if another mobile station has data buffered that is in a
higher priority queue, the network should not allow a mobile
station to send data from RB#4 because of its very low data
priority. Instead it would be preferable for the network to
allocate resources to the mobile station with the highest priority
data.
On the other hand, preventing mobile stations from transmitting low
priority data when high priority data is buffered by other mobile
stations may result in a "starvation" effect wherein the low
priority data may be queued indefinitely or otherwise for an
inordinate amount of time.
The 3.sup.rd Generation Partnership Project Technical Standard,
3GPP TS 25.309, describes procedures adopted for a shared uplink
channel, Enhanced Dedicated Channel (E-DCH) for UMTS networks. Per
the standard, a mobile station may send the identity of the highest
priority logical channel with data in buffer and the total amount
of data in its buffer across all the radio bearers. Because the
uplink is designed as a synchronous Hybrid Automatic Repeat Request
(HARQ) channel, the mobile station may then choose data from all of
its radio bearers as long as it does not exceed the resources
assigned.
In the enhanced uplink the mobile sends a "happy bit" when the time
required to transmit data in radio bearers mapped to scheduled
transmissions, as opposed to non-scheduled transmissions, exceeds a
Happy bit delay condition. This procedure is applied for all radio
bearers utilizing scheduled grants. Unfortunately, there is no
ability to discriminate between radio bearers with different
priorities.
Thus, there is a need for apparatuses and methods for restricting a
mobile station usage of resource grants for transmission of data
while avoiding starvation of low priority data.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a wireless packet communication
network wherein mobile stations may buffer data of various
priorities.
FIG. 2 is block diagram of a mobile station transmission buffer
wherein data of various priorities is buffered and/or queued.
FIG. 3 is diagram showing a mobile station and base station
architecture in accordance with various embodiments.
FIG. 4 is block diagram of a mobile station in accordance with
various embodiments.
FIG. 5 is a message flow diagram illustrating basic operation of a
network controller or base station, and a mobile station, in
accordance with the various embodiments.
DETAILED DESCRIPTION
In the various embodiments, a network, at the time resources are
granted, indicates the lowest priority service, or lowest priority
radio bearer for which a mobile may send data. Thus, a fairness
policy is enforced and a mobile station is prevented from
transmitting data from a very low priority radio bearer, unless
explicitly permitted by the network.
Further in the various embodiments, the network avoids starvation
of low priority data, that is, low priority data buffered by a
mobile station and in queue. In such embodiments, the network may
configure the mobile station with a timer. The timer offsets the
data priority minimum indication provided by the network in a
grant. If the timer expires the mobile station may override the
priority floor indication and transmit data from a low priority
buffer.
In some alternate embodiments, the mobile station may, upon
expiration of the timer, provide an indication to the network that
it has pending data buffered for transmission. Unlike the "happy
bit" indicator specified in the standards for an E-DCH, the various
embodiments basis for mobile station indications is triggered by,
and otherwise based upon, network configuration.
The mobile station may start the timer when the first Protocol Data
Unit (PDU) arrives in the buffer for the low priority service, or
low priority radio bearer, or group of radio bearers. The timer may
be reset when either; at least one PDU or some minimum number of
PDUs, based upon for example a desired data rate, have been
transmitted by the mobile from the queue.
Thus, in the various embodiments, by explicitly indicating a
priority floor for which the grant is to be used the network
ensures that a mobile station will not send data from a buffer with
very low priority, particularly when other mobile stations are
waiting to transmit higher priority data. This is especially
important in the case of synchronous transmissions, because a
mobile station in this case is allowed to retransmit a certain
number of times which results in undesired traffic loading on the
uplink. By employing the timing function of the various
embodiments, set by the network, a mobile station may avoid
starvation of low priority data, that is, waiting indefinitely or
otherwise waiting an inordinate time period before low priority
data may be transmitted.
Turning now to the drawings wherein like numerals represent like
components, FIG. 1 illustrates a communications network 100, having
various base stations such as base station 103, and wherein each
base station has a corresponding coverage area. In general, base
station coverage areas may overlap and, in general, form an overall
network coverage area. The base stations may be referred to by
other names such as base transceiver station (BTS), "Node B", and
access node (AN), depending on the technology. A network coverage
area may comprise a number of base station coverage areas, which
may form a contiguous radio coverage area. However, it is not
required to have contiguous radio coverage and therefore a network
coverage area may alternatively be distributed.
Furthermore, each coverage area may serve a number of mobile
stations. Mobile stations may also be referred to as access
terminals (ATs), user equipment (UEs), or other terminology
depending on the technology. A number of bases stations 103 will be
connected to a base station controller 101 via backhaul
connections. The base station controller 101 and base stations form
a Radio Access Network (RAN). The overall network may comprise any
number of base station controllers, each controlling a number of
base stations. Note that the base station controller 101 may
alternatively be implemented as a distributed function among the
base stations 103. Regardless of specific implementations, the base
station controller 101 comprises various modules for packetized
communications such as a packet scheduler, packet segmentation and
reassembly, etc., and modules for assigning appropriate radio
resources to the various mobile stations.
The base stations 103 may communicate with the mobile stations via
any number of standard air interfaces and using any number of
modulation and coding schemes. For example, Universal Mobile
Telecommunications System (UMTS), Evolved UMTS (E-UMTS) Terrestrial
Radio Access (E-UTRA) or CDMA2000 may be employed. Further, E-UMTS
may employ Orthogonal Frequency Division Multiplexing (OFDM) and
CDMA2000 may employ orthogonal spreading codes such as the Walsh
codes. Semi-orthogonal spreading codes may also be utilized to
achieve additional channelization over the air interface. Further
the network may be an Evolved High Rate Packet Data (E-HRPD)
network. Any appropriate radio interface may be employed by the
various embodiments.
In some embodiments, mobile stations may be grouped and for each
mobile station group, a scheduling function of the base station
controller 101, or base station 103, may assign a set of
time-frequency resources to be shared by the mobile stations in the
group. An indication of the set of shared resources and an ordering
pattern may be signaled from the base station 103 to the mobile
stations using a control channel. Further, the control channel may
be transmitted in any frame with a pre-defined relationship with
the beginning frame of the set of shared resources. The set of
shared resources may begin in the same frame the control channel is
transmitted, may have a fixed starting point relative to the frame
that the control channel is transmitted, or may be explicitly
signaled in the control channel. In any case, the various
embodiments will employ a grant message for allocating resources to
a mobile station and a scheduling message indicating a minimum data
priority.
In the various embodiments, mobile stations will utilize radio
bearers to transmit protocol data units (PDUs) wherein the radio
bearers may be mapped to a set of predetermined services. Mobile
stations may thus be utilizing multiple services simultaneously and
may therefore buffer data for transmission wherein the data has
various priorities. Thus some mobile stations 105 may have only
high priority data buffered and waiting to be transmitted, whereas
other mobile stations 107 may only have low priority data waiting
for transmission. Additionally, some mobile stations 109 may have a
mix of high a low priority data.
FIG. 2 illustrates a mobile station 200, which communicates with a
wireless network 203 via a wireless interface 205 which may include
a dedicated channel or enhanced dedicated channel in some
embodiments. The mobile station 200 has a memory comprising
buffered data 201, which further comprises sets of PDUs 207
associated with various services and/or radio bearers. As discussed
above, specific services may be mapped to specific radio bearers in
the various embodiments.
In the example of FIG. 2, a mobile station having a mix of high and
low priority data, such as mobile stations 109 in FIG. 1 is
illustrated. In FIG. 2, a first set of PDUs is shown buffered
having a first or high priority and corresponding to a first radio
bearer, that is, priority #1 data mapped to radio bearer #1 209.
Similarly, a second set of PDUs is shown buffered having a second
level priority and corresponding to a second radio bearer, that is,
priority #2 data mapped to radio bearer #2 211.
In the FIG. 2 example, no level 3 data is buffered and thus no
priority #3 data, which is mapped to radio bearer #3 213, is
stored. Also in FIG. 2, data is buffered for priority #4 mapped to
radio bearer #4 215. It is thus to be understood that data may be
stored having any mix of priorities wherein any specific priority
may be mapped to a specific radio bearer as exemplified by FIG. 2.
Given a granted set of resources, the mobile station 200 would
proceed to transmit its highest priority data 209, proceed to its
lower priority data 211, and finally transmit its lowest priority
data 215.
Returning briefly to FIG. 1, if the set of mobile stations having
only low priority data, that is mobile stations 107, are granted
resources, the mobile stations would proceed to transmit low
priority data which utilizes resources needed by the higher
priority mobile stations, that is, the mobile stations 105 having
high priority data queued.
Turning now to FIG. 3, a mobile station 300 and base station 301
architectures in accordance with the various embodiments are
illustrated. Mobile station 300 comprises a stack having a VoIP
application 305, a networking layer 307, a Radio Link Controller
(RLC) 309, a Medium Access Controller (MAC) 311, and a Physical
Layer (PHY) 313. In addition, mobile station 300 has HARQ component
315, which may be separate or may be integrated into any of the
other components/layers. The mobile station 301 HARQ component 315
may receive messages for determining resource allocations for
transmitting or receiving data. The mobile station may transmit and
receive various messages to and from the base station on the
physical layer 313.
In accordance with the embodiments, mobile station 300 has a data
buffer or data buffers 304 for storing data associated with a
service, radio bearer and/or priority. Further, mobile station 300
has a data timer 303, the time being determined by the network and
sent to mobile station 300 in a control message in some
embodiments. The data timer 303 is used to determine a length of
time that low priority data, specifically in some embodiments, data
below a predetermined priority minimum, is stored in data buffers
304. If the low priority data is stored longer than the data timer
303, then the low priority data may be transmitted by mobile
station 300 on granted resources.
The base station 301, similar to mobile station 300, has a VoIP
application 317, a networking layer 319, a RLC 321, MAC 323 and PHY
325. However, base station 301 additionally may have in some
embodiments a HARQ scheduling component 327. The base station 301
HARQ scheduling component 327 may send various messages to mobile
stations for indicating their resource allocations for transmitting
or receiving data. Further, the HARQ scheduling component 327 may
define HARQ subgroups in some embodiments.
The base station of some embodiments also comprises data
prioritization module 302. The data prioritization module 302 may
be a separate module as shown, or may be integrated into various
other modules such as HARQ scheduling component 327. Further, the
modules shown in FIG. 3 may be distributed between a base station
and network controller, such as the network controller 101 and base
station 103 illustrated in FIG. 1.
Returning to FIG. 3, data prioritization module 302 determines a
minimum data priority level for which mobile stations may transmit
data over granted resources. The minimum priority level is dynamic
and may be determined by various network conditions such as
throughput, delay, etc., and may in some embodiments be
communicated to the mobile stations via a scheduling message.
The data prioritization module 302, in accordance with some
embodiments, may further determine a time in which low priority
data may not be transmitted, but after which, low priority data may
be transmitted, by a mobile station, or in some circumstances, a
group of mobile stations. The timing information may also be
dynamic based upon network conditions as discussed above with
respect to the priority minimum. The timing information may be
communicated to the mobile stations via a control message.
FIG. 4 is a block diagram illustrating the primary components of a
mobile station in accordance with some embodiments. Mobile station
400 comprises user interfaces 401, at least one processor 403, and
at least one memory 405. Memory 405 has storage sufficient for the
mobile station operating system 407, applications 409 and general
file storage 411. Mobile station 400 user interfaces 401, may be a
combination of user interfaces including but not limited to a
keypad, touch screen, voice activated command input, and gyroscopic
cursor controls. Mobile station 400 has a graphical display 413,
which may also have a dedicated processor and/or memory, drivers
etc. which are not shown in FIG. 4.
It is to be understood that FIG. 4 is for illustrative purposes
only and is for illustrating the main components of a mobile
station in accordance with the present disclosure, and is not
intended to be a complete schematic diagram of the various
components and connections therebetween required for a mobile
station. Therefore, a mobile station may comprise various other
components not shown in FIG. 4 and still be within the scope of the
present disclosure.
Returning to FIG. 4, the mobile station 400 may also comprise a
number of transceivers such as transceivers 415 and 417.
Transceivers 415 and 417 may be for communicating with various
wireless networks using various standards such as, but not limited
to, UMTS, E-UMTS, E-HRPD, CDMA2000, 802.11, 802.16, etc.
Memory 405 is for illustrative purposes only and may be configured
in a variety of ways and still remain within the scope of the
present disclosure. For example, memory 405 may be comprised of
several elements each coupled to the processor 403. Further,
separate processors and memory elements may be dedicated to
specific tasks such as rendering graphical images upon a graphical
display. In any case, the memory 405 will have at least the
functions of providing storage for an operating system 407,
applications 409 and general file storage 411 for mobile station
400. In some embodiments, and as shown in FIG. 3, applications 409
may comprise a software stack that communicates with a stack in the
base station. In the various embodiments, file storage 411 may
comprise the data buffers 421 for storing data of various priority
levels prior to transmission.
Also in the various embodiments, applications 419 may include a
data timer 409 for determining when low priority data stored in
data buffers 421 may be transmitted over granted resources.
FIG. 5 summarizes operation of a network controller or base
station, and a mobile station in accordance with the various
embodiments. The network controller or base station 502, allocates
resources and indicates a minimum priority level below which, the
mobile stations should not transmit data via messaging 503.
Messaging 503 may be a scheduling message in some embodiments.
The network controller or base station 502 also communicates a data
timer setting for timing sub-minimum priority data via messaging
505. Messaging 505 may be a control message in some embodiments.
The mobile station 501 responds by setting a data timer 507 and
holding data with a priority below the specified minimum. Before
the timer times out, the mobile station 501 may transmit data on
granted resources via 509 provided its priority level is above the
specified minimum.
After expiration of the timer, the mobile station 501 may transmit
its low priority data, or combinations of high and low priority
data via transmission 511.
The mobile station may either transmit low priority data until its
buffered data is exhausted or in some embodiments may transmit only
a percentage of the data is transmitted. In such embodiments, the
network may also specify the data percentage to be transmitted
after expiration of the timer. The percentage may be communicated
to the mobile stations via messaging 505 which may be a control
message as discussed above.
The timer function may be dynamically updated during a subsequent
message 505. Likewise the data priority may be raised or lowered in
subsequent scheduling messages 503. Alternatively, in some
embodiments, the mobile station will reset the timer after the low
priority data transmission percentage, which was also specified in
messaging 505, was satisfied.
While various embodiments have been illustrated and described, it
is to be understood that the invention is not so limited. Numerous
modifications, changes, variations, substitutions and equivalents
will occur to those skilled in the art without departing from the
spirit and scope of the present invention as defined by the
appended claims.
* * * * *